Foamed articles and methods of making the same

Abstract

Foamed articles including a foamed thermoplastic elastomeric material, methods of making the foamed articles, and methods for manufacturing articles of footwear, apparel, and athletic equipment incorporating such foamed articles are provided. In one aspect, a method for making a foamed article comprises placing an article comprising a foamable material and carbon dioxide in a vessel, maintaining the vessel at a first pressure and first temperature at which the carbon dioxide is a liquid and carbon dioxide is soluble in the foamable material, optionally exposing the infused article to a second temperature and second pressure, and subjecting the article to a third pressure and third temperature at which the infused carbon dioxide phase transitions to a gas, thereby expanding the foamable material into a foamed material and forming the foamed article.

What is claimed is: 
     
         1 . A method for making a foamed article, the method comprising:
 placing an article and carbon dioxide in a vessel, wherein the article comprises a solid foamable material which is a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers;   after the placing, maintaining the vessel at a first pressure and first temperature, wherein the first pressure and first temperature are a pressure and temperature at which the carbon dioxide is a liquid and the liquid carbon dioxide is soluble in the solid foamable material, and wherein the maintaining includes holding the article and the liquid carbon dioxide in the vessel for a duration of time sufficient for at least a portion of the liquid carbon dioxide to infuse into the solid foamable material of the article;   following the maintaining and holding, optionally exposing the infused article to a second pressure and second temperature at which the carbon dioxide remains infused within at least a portion of the solid foamable material;   following the maintaining and holding and the optional exposing, subjecting the article to a third pressure and third temperature at which the carbon dioxide infused in the solid foamable material phase transitions to a gas, thereby expanding the solid foamable material into a foamed material and forming the foamed article.   
     
     
         2 . The method of  claim 1 , further comprising following the subjecting and expanding, bringing the foamed article to a fourth temperature and fourth pressure, and holding the foamed article at or below the fourth temperature, the fourth pressure, or both, for a duration of time. 
     
     
         3 . The method of  claim 1 , further comprising following the subjecting and expanding, stabilizing the foamed article at a fifth pressure and fifth temperature at which the carbon dioxide diffuses out of the foamed material of the foamed article while maintaining the foamed material in a foam structure, forming a stabilized foamed article. 
     
     
         4 . The method of  claim 3 , wherein the stabilizing comprises holding the foamed article at the fifth pressure and fifth temperature for a duration of time sufficient to remove substantially all of the carbon dioxide from the foamed material. 
     
     
         5 . The method of  claim 1 , wherein, at the first pressure and temperature, the liquid carbon dioxide is soluble in the solid foamable material at a concentration of from about 1 weight percent to about 30 weight percent based on a total weight of the solid foamable material. 
     
     
         6 . The method of  claim 1 , wherein the one or more first thermoplastic elastomers comprise one or more thermoplastic elastomeric polyolefin homopolymers or copolymers, one or more thermoplastic elastomeric polyamide homopolymers or copolymers, one or more thermoplastic elastomeric polyester homopolymers or copolymers, one or more thermoplastic elastomeric polyurethane homopolymers or copolymers, one or more thermoplastic elastomeric styrenic homopolymers or copolymers, or any combination thereof. 
     
     
         7 . The method of  claim 6 , wherein the one or more first thermoplastic elastomers of the foamable material comprises one or more thermoplastic elastomeric polyester-polyurethane copolymers. 
     
     
         8 . The method of  claim 1 , wherein the steps of maintaining and holding comprise maintaining the first pressure of from about 0.05 pounds per square inch (0.345 kilopascals) to about 2000 pounds per square inch (13,790 kilopascals) and maintaining the first temperature of from about −57 degrees Celsius to about 31 degrees Celsius. 
     
     
         9 . The method of  claim 1 , wherein the optional step of exposing comprises exposing the article to the second pressure of from about 1 atmosphere (101 kilopascals) to about 85 atmospheres (8613 kilopascals). 
     
     
         10 . The method of  claim 1 , wherein the optional step of exposing comprises exposing the article to the second temperature of more than about 30 degrees below the softening point of the solid foamable material. 
     
     
         11 . The method of  claim 1 , wherein the steps of subjecting and expanding comprise subjecting the article to the third pressure of from about 13 pounds per square inch (89.6 kilopascals) to about 16 pounds per square inch (110.3 kilopascals) and subjecting the article to the third temperature of from about 20 degrees Celsius to about 150 degrees Celsius. 
     
     
         12 . The method of  claim 2 , wherein the step of bringing comprises bringing the foamed article to the fourth pressure of from about 0.03 atmospheres (3.04 kilopascals) to about 2 atmospheres (202.65 kilopascals) and bringing the foamed article to the fourth temperature of from about 30 degrees Celsius to about 70 degrees Celsius. 
     
     
         13 . The method of  claim 1 , wherein the step of subjecting and expanding comprises expanding the foamable material into the foamed material until the foamed material has a density of from about 0.01 gram per cubic centimeter to about 0.1 gram per cubic centimeter. 
     
     
         14 . The method of  claim 1 , wherein the solid foamable material has a Shore A hardness of from about 35 A to about 95 A. 
     
     
         15 . A foamed article comprising:
 a foamed material which is a physically-expanded foam formed of a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers, wherein the foamed material is a product of placing an unfoamed article comprising a solid foamable material in liquid carbon dioxide, infusing the solid foamable material with the liquid carbon dioxide, and expanding the infused solid foamable material by phase transitioning the infused carbon dioxide into a gas under conditions which do not soften the solid foamable material, thereby forming the foamed material of the foamed article.   
     
     
         16 . The foamed article of  claim 15 , wherein the foamed article is a stabilized foamed article comprising a stabilized foamed material. 
     
     
         17 . The foamed article of  claim 15 , wherein the one or more first thermoplastic elastomers comprise or consist essentially of one or more thermoplastic polyurethane elastomeric homopolymers or copolymers. 
     
     
         18 . The foamed article of  claim 15 , wherein the foamed article comprises an additional material, wherein the additional material is a separate material from the foamed material, and wherein the additional material is unfoamed. 
     
     
         19 . The foamed article of  claim 15 , wherein the foamed material has a density of from about 0.01 gram per cubic centimeter to about 0.1 gram per cubic centimeter. 
     
     
         20 . The foamed article of  claim 15 , wherein the foamed article is an article of apparel, footwear or sporting equipment, or is a component of an article of apparel, footwear or sporting equipment.